Results 61 to 70 of about 855 (105)

On the Classical-Quantum Relation of Constants of Motion

open access: yesFrontiers in Physics, 2018
Groenewold-Van Hove theorem suggest that is not always possible to transform classical observables into quantum observables (a process known as quantization) in a way that, for all Hamiltonians, the constants of motion are preserved.
Fabian Belmonte   +3 more
doaj   +1 more source

A Parametric Network Approach for Concepts Hierarchy Generation in Text Corpus

open access: yesAnalele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2016
The article presents a preflow approach for the parametric maximum flow problem, derived from the rules of constructing concepts hierarchy in text corpus.
Sângeorzan L. S.   +2 more
doaj   +1 more source

A Note on Graph Burning of Path Forests [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science
Graph burning is a natural discrete graph algorithm inspired by the spread of social contagion. Despite its simplicity, some open problems remain steadfastly unsolved, notably the burning number conjecture, which says that every connected graph of order $
Ta Sheng Tan, Wen Chean Teh
doaj   +1 more source

Polynomial algorithms that prove an NP-hard hypothesis implies an NP-hard conclusion [PDF]

open access: yes, 1999
A number of results in Hamiltonian graph theory are of the form $\mathcal{P}$$_{1}$ implies $\mathcal{P}$$_{2}$, where $\mathcal{P}$$_{1}$ is a property of graphs that is NP-hard and $\mathcal{P}$$_{2}$ is a cycle structure property of graphs that is ...
Bauer, D.   +3 more
core   +2 more sources

$2$-polarity and algorithmic aspects of polarity variants on cograph superclasses [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science
A graph $G$ is said to be an $(s, k)$-polar graph if its vertex set admits a partition $(A, B)$ such that $A$ and $B$ induce, respectively, a complete $s$-partite graph and the disjoint union of at most $k$ complete graphs.
Fernando Esteban Contreras-Mendoza   +1 more
doaj   +1 more source

The agreement distance of rooted phylogenetic networks [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2019
The minimal number of rooted subtree prune and regraft (rSPR) operations needed to transform one phylogenetic tree into another one induces a metric on phylogenetic trees - the rSPR-distance.
Jonathan Klawitter
doaj   +1 more source

The metric dimension and metric independence of a graph [PDF]

open access: yes, 2001
A vertex x of a graph G resolves two vertices u and v of G if the distance from x to u does not equal the distance from x to v. A set S of vertices of G is a resolving set for G if every two distinct vertices of G are resolved by some vertex of S. The
Currie, James, Oellerman, Ortrud R.
core  

Evaluating a weighted graph polynomial for graphs of bounded tree-width [PDF]

open access: yes, 2009
We show that for any $k$ there is a polynomial time algorithm to evaluate the weighted graph polynomial $U$ of any graph with tree-width at most $k$ at any point.
Noble, S D
core  

Exponential Generalised Network Descriptors

open access: yes, 2016
In communication networks theory the concepts of networkness and network surplus have recently been defined. Together with transmission and betweenness centrality, they were based on the assumption of equal communication between vertices.
Antunović, Suzana   +3 more
core   +4 more sources

On the number of pancake stacks requiring four flips to be sorted [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2019
Using existing classification results for the 7- and 8-cycles in the pancake graph, we determine the number of permutations that require 4 pancake flips (prefix reversals) to be sorted.
Saúl A. Blanco   +2 more
doaj   +1 more source

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